Working on Yanclone/186F fuel pump

[luizbenjamin]

Dos anybody know what to modify in a plain generator type (constant speed) fuel pump, to became a "variable speed" type fuel pump.
I have removed the governor (weight only, not the gear) and attached the accelerator cable direct to the lever that connects to the pump fuel control. The engine starts at full throttle, accepts changes on rpm (going up and down), but only takes high idle speed (2200 rpm). I noted some comments about a different fuel pump (my it is for generator, to be working at full speed all the time), that can give me a low and steady idle speed.
I saw one in the England eBay (http://www.ebay.com/itm/280978098005?ss ... 1423.l2649), but they do not ship to USA.
I will be using this engine on a racing kart, but need the idle speed more reliable and lower them 1800 rpm (clutch engages at 2000 rpm).